+(defun special-variable-p (x)
+ (and (claimp x 'variable 'special) t))
+
+;;; Wrap CODE to restore the symbol values of the dynamic
+;;; bindings. BINDINGS is a list of pairs of the form
+;;; (SYMBOL . PLACE), where PLACE is a Javascript variable
+;;; name to initialize the symbol value and where to stored
+;;; the old value.
+(defun let-binding-wrapper (bindings body)
+ (when (null bindings)
+ (return-from let-binding-wrapper body))
+ (concat
+ "try {" *newline*
+ (indent "var tmp;" *newline*
+ (mapconcat
+ (lambda (b)
+ (let ((s (ls-compile `(quote ,(car b)))))
+ (concat "tmp = " s ".value;" *newline*
+ s ".value = " (cdr b) ";" *newline*
+ (cdr b) " = tmp;" *newline*)))
+ bindings)
+ body *newline*)
+ "}" *newline*
+ "finally {" *newline*
+ (indent
+ (mapconcat (lambda (b)
+ (let ((s (ls-compile `(quote ,(car b)))))
+ (concat s ".value" " = " (cdr b) ";" *newline*)))
+ bindings))
+ "}" *newline*))
+
+(define-compilation let (bindings &rest body)
+ (let* ((bindings (mapcar #'ensure-list bindings))
+ (variables (mapcar #'first bindings))
+ (cvalues (mapcar #'ls-compile (mapcar #'second bindings)))
+ (*environment* (extend-local-env (remove-if #'special-variable-p variables)))
+ (dynamic-bindings))
+ (concat "(function("
+ (join (mapcar (lambda (x)
+ (if (special-variable-p x)
+ (let ((v (gvarname x)))
+ (push (cons x v) dynamic-bindings)
+ v)
+ (translate-variable x)))
+ variables)
+ ",")
+ "){" *newline*
+ (let ((body (ls-compile-block body t)))
+ (indent (let-binding-wrapper dynamic-bindings body)))
+ "})(" (join cvalues ",") ")")))
+
+
+;;; Return the code to initialize BINDING, and push it extending the
+;;; current lexical environment if the variable is special.
+(defun let*-initialize-value (binding)
+ (let ((var (first binding))
+ (value (second binding)))
+ (if (special-variable-p var)
+ (concat (ls-compile `(setq ,var ,value)) ";" *newline*)
+ (let* ((v (gvarname var))
+ (b (make-binding var 'variable v)))
+ (prog1 (concat "var " v " = " (ls-compile value) ";" *newline*)
+ (push-to-lexenv b *environment* 'variable))))))
+
+;;; Wrap BODY to restore the symbol values of SYMBOLS after body. It
+;;; DOES NOT generate code to initialize the value of the symbols,
+;;; unlike let-binding-wrapper.
+(defun let*-binding-wrapper (symbols body)
+ (when (null symbols)
+ (return-from let*-binding-wrapper body))
+ (let ((store (mapcar (lambda (s) (cons s (gvarname s)))
+ (remove-if-not #'special-variable-p symbols))))
+ (concat
+ "try {" *newline*
+ (indent
+ (mapconcat (lambda (b)